Single thread knotted lockstitch seam



Oct. 22, 1968 M. K. ROHRLICK ETAL 3,406,547

SINGLE THREAD KNOTTED LOCKSTITCH SEAM Filed Feb. 20, 1967 W n ran: IMic/me! If. ROI/ Brian United States Patent 3,406,647 SINGLE THREADKNOTTED LOCKSTITCH SEAM Michael K. Rohrlick and Brian Clein, Montreal,Quebec, Canada, assignors to Elwood Realties Ltd., Lachrne, Quebec,Canada, a corporation of Canada Filed Feb. 20, 1967, Ser. No. 617,312 4Claims. (Cl. 112-438) ABSTRACT OF THE DISCLOSURE A novel type of singlethread sewing stitch characterized in that a loop of the thread ispushed through the material at each of a series of consecutive stitchpoints and the base portion of each loop is attached to the end portionof the adjacent previous loop by making one backwardly pitching turntherearound and forwardly around itself and hence through the said endportion.

The present invention relates to the art of forming seams by means ofsuccessive stitches or chain stitches and particularly to a novel ravelproof stitch.

The novel stitch of the present invention may be defined as a ravelproof, seam forming, single thread, knotted lockstitch.

Single thread lockstitches are known as such and belong to an art whichmay be examplified by US. Patent No. 3,224,399 of Dec. 21, 1965, forinstance.

Lockstitched seams are seams which are not susceptible to unravellingfrom some skipped or ruptured stitch positions. Seams formed of stitchessuch as outlined in the US. Government publication entitled FederalStandard No. 751a, classes 300 and 700 therein, have for their generalcharacteristic, the interlacing of the threads. Interlacing requiresthat a quantity of thread be wound onto a bobbin or reel in the lowermechanism of a sewing machine. Since it is necessary for this bobbin orreel to pass through the loop formed by the needle of the machine, itfollows that there is a practical limit to the size which may be givento the bobbin and therefore, to the actual amount or length of threadwhich may be held in reverse therein. As a result, frequentreplenishment of the thread supply of the bobbin occasions equallyfrequent sewing work stoppages; this is a disadvantage which the presentinvention seeks to eliminate.

It is an object of the present invention to produce a seam whichconsists of positively interlocked stitches whereby unravelling of theseam in the event of any skipped or ruptured stitch is renderedimpossible.

It is a further object of the invention to present a seam the stitchesof which are formed from a single thread, thereby eliminating thenecessity for using bobbins or reels in the lower mechanism of thesewing machine and for attending to their frequent replenishment.

It is a further object of the invention that the seam shall consist ofstitches formed by the interlooping of the thread with itself ratherthan by the interlacing of one thread with itself or with anotherthread.

A better understanding of the invention will be had hereinafter from thedisclosure of an embodiment of the invention, reference being bad to theannexed drawing wherein:

FIG. 1 is a perspective view of a scam in accordance with the presentinvention, the material in which the seam is practiced not being shownfor the sake of clarity;

FIG. 2 is a top plan view of a seam in accordance with the invention;

FIG. 3 is a vertical cross section of the same, taken along line 3-3 ofFIG. 2;

FIG. 4 is a bottom plan view of the same and FIG. 5 is an enlargedperspective view of a stitch in accordance with the invention andwherein the thread is shown loosened for easier visualizing.

In FIGS. 2, 3 and 4 the stitched seam is observed to be applied to twosuperposed layers of fabric 11 and 12. A single thread 13 is usedthroughout to form the seam. Loops of the thread 13 are passed throughthe layers 11 and 12 of the fabric at evenly spaced intervals by meansof appropriate pointed instruments such as by means of a conventionaleye pointed needle. A series of successive points at which the loops ofthe thread are passed through the layers of fabric 11 and 12 areindicated at 14 through 18 inclusively. The illustrated seam is formedby successive stitches and progresses from left to right as indicated byarrow 6.

In the fomation of the stitches illustrated in FIGS. 2, 3 and 4, thefirst loop 30 is temporarily detained by proper retainer means, such asby means of a hook. The following loop 31 which projects through thefabric layers 11 and 12 at 15 is taken around the bight 20 of loop suchas by means of a looper or similar device. The loop 31 is then passedover itself at point 21 and therefrom through the bight 20 of loop 30.The loop 31 thus formed is pulled tight such as by means of theaforementioned hook (not shown in the drawing) which had previouslyretained the bight'ZO of loop 30. The bight 23 of loop 31 is nowpositioned for the next stitch to be made by the loop 32 formed at pointof penetration 16.

We claim:

1. A stitch for the production of seams in fabric and the like materialsfrom a single thread and characterized in that, at spaced apart pointsalong a seam line, loops of said thread project through the material,each loop presenting a bight which is located adjacent the point atwhich the next loop projects through the material, said next loop firstencircling the bight portion of the previous loop, then passing arounditself and finally projecting through the bight of the said previousloop.

2. A stitch in a seam comprising a series of consecut1ve stitches in amaterial and formed from a single thread, said stitches beingcharacterized in that they each present a loop projecting through thematerial, each loop extending across and terminating at a positionadjacent to the corresponding loop of the next stitch and presenting abight, said loop of the next stitch encircling the adjacent portion ofthe first mentioned loop, extending around itself from behind andpassing through the bight of said first mentioned loop.

3. A seam of stitches in a material, said stitches produced from asingle thread generally extending longitudinally of said seam andcharacterized in that each stitch comprises a loop of the thread whichis forced through said material, encircles the end portion of thecorresponding loop of the previous stitch and then passes around itselfand through the end of the said corresponding loop of the previousstitch.

4. A single thread knotted lockstitch seam presenting a series ofconsecutive stitches through a material, each stitch consisting of aloop of the single thread passing through the material from one side tothe reverse side thereof, extending therefrom fully around the loop ofthe preceding stitch and thence around itself and through the said loopof the preceding stitch to terminate in the vicinity of the followingstitch.

References Cited UNITED STATES PATENTS 23,984 5/1859 McCurdy 1124381,657,989 1/1928 Baker 112-197 2,906,224 9/1959 Henry 112-262 3,224,39912/ 1965 Lightner et al. 112-262 RICHARD J. SCANLAN, JR., PrimaryExaminer.

